import math
list = []
while True: 
    a = input("请输入数字(直接输入回车退出):")
    if a == "" :
        break
    else :
        a1 = int(a)
        list.append(a1)
#求和
def sum(list):
    a= 0
    for i in list:
        a = i+a
    return a
  
#求平均值
def average(list):
     return sum(list) / len(list)

#求标准差
def standard_deviation(list):
    sum = 0
    for i in list:
        sum = (i - ave)**2 + sum
    a = sum / (len(list)-1)
    return math.sqrt(a)


#求中位数
def median(list):
    a=len(list)
    sorted_list = sorted(list)
    if a % 2 == 0:
        a1 = a/2 -1
        a2 = a/2 
        b=(sorted_list[int(a1)]+sorted_list[int(a2)])/2
    elif a % 2 != 0:
        a1 = (a+1)/2 - 1
        b = sorted_list[int(a1)]
    return b
    

ave=average(list)
median_num = median(list)
dev=standard_deviation(list)
print(f"平均值:{ave:.2f},标准差:{dev:.2f},中位数:{median_num}")
